The first Tzimtzum left an empty space that was darkness and void. The absence of light allowed darkness to be judgments because the opposite of light that is mercy, is judgment. A world without light can not exists in constant chaos.
The second Tzimtzum elevated Malchut to the level of Binah in order to create a world of Tikkun and build a desire for the light in the vessels below.
The entire process had one purpose , which was to mix judgment with mercy, allowing people to follow the Torah in order to draw light and enjoy mercy.
The Torah and the names of God were given to us as a tool to make a personal Tzimtzum and elevate our souls to Binah.